1.4C Impacts of Tectonic Hazards
The social and economic impacts of tectonic hazards (volcanic eruptions, earthquakes and tsunami) on the people, economy, and environment of contrasting locations in the developed, emerging and developing world.
The impacts of tectonic hazards are broadly of three types:
- social - deaths, injury and wider health impacts including psychological ones
- economic - the loss of property, businesses, infrastructure and opportunity
- environmental - damage or destruction of physical systems, especially ecosystems
In the last 30 years, different tectonic hazards have had contrasting impacts in terms of scale.
Volcanic eruptions: Small and declining impacts, especially death tolls
Earthquakes: Large impacts, as significant earthquakes are common and widespread
Tsunami: Very large impacts from a small number of events
Comparing impacts between countries is difficult because both the physical nature of the event and the socio-economic profiles of affected places are different. Some general observations are:
- economic costs in developed and emerging economies are, in some cases, enormous
- deaths in developed countries are low, except for the 2011 Japanese tsunami (a very rare megadisaster)
- volcanic eruption impacts are small compared with those of earthquakes and tsunami
Volcanic eruptions
2002 Nyiragongo (DRC)
About:
Response
- Constructive margin, continental rift zone
- Basaltic magma
- Composite cone volcano (a..k.a. stratovolcano)
- VEI = 1
- 147 deaths
- 120,000 made homeless
- 15% of the city of Goa destroyed by lava flows
- US $1.2 billion in economic losses
Response
- Major international aid response launched
2010 Merapi (Indonesia)
About
Social Impacts:
- Destructive margine subduction zone
- Andesitic magma
- Composite cone volcano
- VEI = 4
Social Impacts:
- 353 deaths
- about 500 injured
- 350,000 people evacuated before the eruption
- $0.6 billion in losses
- Loss of rice harvest due to ash fall
- Some destruction of forests due to pyroclastic flows
2010 Eyjafjallajökull (Iceland)
About:
Social Impacts:
- Constructive margin
- Mid-ocean ridge
- Basaltic magma
- Composite cone volcano (stratovolcano)
- VEI = 4 (same year and VEI as Merapi)
Social Impacts:
- No injuries
- No deaths
- Major disruption to European and transatlantic air travel affecting 10 million passengers
- and costing $10 million in economic losses
- Ice melt on the volcano caused some flash flooding
Earthquakes
2015 Gorkha (Nepal)
- Magnitude = 7.9
- Focal depth = 8.2 km
- Continent-continent collision zone
Social Impacts:
- 9000 deaths
- 22,000 injured
- Many rural villages totally destroyed
- $5 billion in losses
- Many rural villages totally destroyed
- Some destruction of forests due to pyroclastic flows
- Killer avalanches triggered on Mount Everest
2008 Sichuan (China)
About
Social Impacts:
- Magnitude 8.0
- Focal depth = 19 km
- Continent-continent collision zone (same as Gorkha)
Social Impacts:
- 69,000 deaths
- About 1/3 of deaths (23,000) due to landslides
- 370,000 injured
- At least 5 million homeless
- More than $140 billion in losses
2010 Canterbury (New Zealand)
About:
Social Impacts:
- Magnitude 7.1
- Focal depth = 10 km
- Subduction zone
Social Impacts:
- 100 injuries
- No deaths (same as Eyjafjallajokull)
- A magnitude 6.3 aftershock in Christchurch killed 185 people
- $40 in total losses (including aftershocks)
- Widespread building damage due to liquefaction
Tsunami
2004 Indian Ocean
About:
- Magnitude 9.2
- 24 m tsunami height
- Megathrust subduction zone
- 230,000 deaths
- 125,000 injured
- 1.7 million people displaced across 15 countries
- $15 billion in economic losses
2010 Talcahuano (Chile)
About:
Social Impacts
- Magnitude 8.8
- 2.6 m tsunami height
- Megathrust subduction zone
- Overall, the earthquake was more damaging than the accompanying tsunami
Social Impacts
- 525 deaths
- Felt by 80% of the population
- Blackout that affected 93% of the population
- 370,000 homes damaged
- Economic costs of $15-30 billion to Chile, and $67 million to Japan (fishing in Tôhoku)
2011 Tôhoku (Japan)
About:
Social impacts
- Magnitude 9.0 (median of Talcahuano and Indian Ocean)
- 9.3 m tsunami height
- Megathrust subduction zone (all are)
Social impacts
- 16,000 deaths
- 6000 injuries
- $300 billion in economic losses
- 46,000 buildings destroyed
- 145,000 buildings damaged
- Huge infrastructure damage to ports, water and electricity supply